Circuit-protective device.



W. D. PYLE.

CIRCUIT PROTECTIVE DEVICE.

APPLICATION FILED JULY 104912.

1,272,090. PatentedJuly 9,1918.

WITNESSES I 2 ATTORNEY WILLIAM D. PYLE, 0F INDIANAPOLIS, INDIANA.

CIRCUIT-PROTECTIVE DEVICE.

Specification of Letters Patent.

Patented July 9, 1918.

Application filed July 10, 1917. Serial No. 179,740.

To all whom it may concern:

Be it known that I, WILLIAM D. Pm, a citizen of the United States,residing at Indianapolis, in the county of Marion and State of Indiana,have invented new and useful Improvements in Circuit-Protective Devices,of which the following is a specification.

This invention relates to improvements in devices for protectingelectric circuits from excessive currents, and has for its objects toprovide a simple, substantial, and eiiicient device which may be used anindefinite number of times Without renewal. It is further proposed toincorporate in the device means whereby the circuit will be permanentlyinterrupted following the operation of the device until it is manuallyrestored to normal condition.

From the description below taken in connection, with the drawings, theconstruction and operation of the device will be readily understood.

In the drawings Figure 1 is a side elevation.

Fig. 2 is a longitudinal section through the device.

Fig. 3 is a transverse section on the line 3 3 of Fig. 2.

Fig. 1 is a section on line 4-4 of Fig. 2.

In the present invention a column of conducting liquid, preferablymercury, constitutes the circuit-breaking element.

As shown in the drawings, the device comprises a hollow cup-like body 1of conducting material, preferably metal, and adapted for connection toone side of a circuit; The body is formed in the inner surface of thebottom with concentric annular grooves or channels constitutingrespectively a mercury reservoir 3 and a pocket 4 for directing mercuryentering the pocket into an opening 5 extending from the bottom of thepocket through the bottom of the body. The reservoir 3 is desirably of alarger capacity than the pocket 4 and reduced in width toward the bottomas shown.

For displacing the mercury in the reservoir 3 to cause it to overflowinto the pocket 4, a plunger 6 loosely inserted in the body 1 has aflange adapted to enter the reservoir 3, the flange being preferably ofsuitable shape to conform to and completely fill the reservoir, thusenabling all the mercury to be utilized. The head of the plunger 6 isattached to a shank 7 slidably mounted in a cap 8 screwthreaded on theend of the body 1 and is terminally provided exteriorly of the cap witha head 9 for manual actuation. A spring 10 bearing against the cap 8 andhead 9 is provided for withdrawing the plunger 6 from the reservoir 3;and vents 11 provided in the plunger 6 prevent formation of a partialvacuum in withdrawing the plunger from a completely depressed position.

The body 1 is formed in the bottom centrally to the pocket 1 with anopening 12 for receiving the reduced extension of a cylindrical plug 13of insulating material inserted in the end of an insulating shell ortube 14 attached outwardly of the bottom, as here shown by screwthreadedengagement with a collar provided on the bottom.

Tightly inserted in the other end of the tube 14 is a conducting plug 15adapted for connection to the other side of the circuit. The insulatingplug 13 is formed with a bore 16 establishing connection at one end withthe opening 5 communicating with the pocket 4, and at the other end withthe adjacent cavity 18 in the tube; and is further formed with a bore 19extending through the extension and constituting a vent for the cavity18.

It will be seen that in the actuation of the plunger the mercury willenter the bores in the plug 13 and the cavity 18 in the tube, andestablish connection between the body 1 and plug 15. The bore 16 isproperly proportioned to the maximum current to be carried by thedevice, so that the contained column of mercury will be partiallyvaporized when overloaded, and the mercury forcibly expelled from thebores to be retained by the reservoir 4 until the plunger 6 is manuallyactuated to reestablish the circuit.

It will be evident that the preferred form of the invention describedand shown constitutes only one of many possible embodiments, and theright is reserved to such variation and use of equivalents as fallswithin the spirit of the invention and the latitude of the claims.

What I claim is:

1. A safety device for an electric circuit comprising a tube, a bodymounted on one end of the tube, said body formed with a pocket inconnection with the bore of the tube and further formed with a reservoiradapted for containing a quantity of liquid,

means for displacing liquid in the reservoir to cause the liquid toenter the pocket and fill the tube, and means for establishing electricconnection with liquid in the tube.

2. A safety device for an electric circuit comprising a tube, a bodymounted on one end of the tube, said body formed with a pocket inconnection with the bore of the tube and further formed with a reservoiradapted for containing a quantity of liquid, means for displacing liquidin the reservoir to cause the liquid to enter the pocket and flow bygravity into the tube, means for establishing electric connection withthe liquid in the tube, and means whereby liquid e2;- pelled from thetube will be directed to enter the reservoir.

- 3. A safety device for an electric circuit comprising a tube formedwith a pair of bores, means on one end of the tube inclosing a cavityconnecting said bores, a conducting body mounted on the other end of thetube, said body formed with an annular pocket surrounding one of thebores and establishing connection with the other bore, said body furtherformed with an annular reservoir surrounding said pocket and adapted forcontaining a quantity of liquid, means for displacing liquid in thereservoir to cause the liquid to enter the pocket and fill the boreconnected with the pocket and means whereby liquid expelled from thebores of the tube will be directed to enter said reser- Volt.

4. In an electric protective device, a cylindrical body closed at'oneend with a bottom and provided on the bottom with an up standing annularrim, and formed in the bottom with a pair of openings terminating in thespace within the rim; an insulating tube attached to the body exteriorlyof the bottom and formed with a pair of bores establishing connectionwith the openings in the body, and-a cap on the tube inclosing a cavityconnecting the ends of the bores; a cap on the body, a headed shankslidalbly inserted in an opening in the cap, and a plunger in the bodyattached to the shank and adapted for entering the space between thewall of the body and the rim.

In testimony whereof I afiix my signature.

WILLIAM D. PYLE.

